Special Senses Flashcards
- conscious or subconscious awareness of changes in the external or internal environment.
Sensation
conscious awareness and interpretation of sensations and is primarily a function of the cerebral cortex (parietal bone)
Perception
T or F
Adaptation - decrease in sensation during a prolonged stimulus
Some receptors are all rapidly adapting,
Your body adapts to different temperatures like when sinking into a hot tub
FLASE
Adaptation - decrease in sensation during a prolonged stimulus
Some receptors are rapidly adapting, others are slow
Your body adapts to different temperatures like when sinking into a hot tub
Sensory receptors - can be classified into:(3 ITEM)
free nerve endings,
encapsulated nerve endings, and
separate sense
General senses of touch (3 items)
Special senses (5 items)
General senses of touch
- Temperature
- Pain
- Pressure
Special senses
- (Smell)
- (Taste)
- Sight
- Hearing
- Equilibrium
Receptors for the special senses are housed in complex sensory organs such as eyes and ears
Special senses
—- - study of the eye and its disorders
——— study of the ears, noes, throat and their disorders
Ophthalmology - study of the eye and its disorders
Otorhinolaryngology - study of the ears, noes, throat and their disorders
what percent of sensory receptor is in the eye
70% of all sensory receptors are in the eyes
T or F
Protection of the eye
Most of the eye is enclosed in a bony orbit
A cushion of fat surrounds most of the eye
True
T or F
Each eye has over a million nerve fibers
True
Membrane that lines the eyelids
non keratinised stratified squamous epithelium
Connects to the surface of the eye
Secretes mucus to lubricate the eye
Conjunctiva
Eyelids & Eyelashes function
Anteriorly, the eyes are protected by the mobile eyelids or palpebrae
The eyelashes protect the eye from foreign objects, perspirations, and sunlight
The —– plate, a connective tissue, gives form and support to the eyelids
The——glands secrete oil to lubricate the eyelid and eye, it also prevents the eyelids from sticking together
The tarsal plate, a connective tissue, gives form and support to the eyelids
The tarsal glands secrete oil to lubricate the eyelid and eye, it also prevents the eyelids from sticking together
The ciliary glands, modified apocrine sweat glands, are found in between eyelash hair follicles
They are also called as glands of moll
Ciliary Gland
The ciliary glands, modified apocrine sweat glands, are found in between eyelash hair follicles
They are also called as glands of moll
Ciliary Gland
Modified sebaceous glands that produce an oily secretion to lubricate the eye
Meibomian Glands
—- gland: produces lacrimal fluid, moistens and lubricates the eye
——canals: drains lacrimal fluid from eyes
Lacrimal gland: produces lacrimal fluid, moistens and lubricates the eye
Lacrimal canals: drains lacrimal fluid from eyes
Tears: composed of?
Tears: composed of diluted salt solution, antibodies, mucous, lysozyme (destroys bacteria)
provides passage of lacrimal fluid towards the nasal cavity and is emptied via the nasolacrimal duct
Lacrimal sac
Explain the flow of tears
Lacrimal gland → lacrimal ducts → ocular surface → lacrimal puncta → lacrimal canaliculi → lacrimal sac → nasolacrimal duct → inferior nasal meatus → nasopharynx
Muscles attach to the outer surface of the eye
Produces eye movements
Extrinsic Eye Muscles
Extrinsic Eye Muscles Consists of four rectus muscles namely: and Also consists of two oblique muscles namely:
Consists of four rectus muscles namely:
- Superior rectus muscle
- Inferior rectus muscle
- Lateral rectus muscle
- Medial rectus muscle
Also consists of two oblique muscles namely:
- Superior oblique muscle
- Inferior oblique muscle
The wall is composed of three tunics:
Fibrous tunic: outer layer
Choroid (Vascular layer): middle layer
Sensory tunic: inner layer
White dense connective tissue layer made up mostly of collagen fibers and fibroblasts
Seen anteriorly as the “white of the eye
Gives shape to the eyeball, makes it more rigid
Sclera
Central, transparent coat that covers the colored iris
Allows for light to pass through and repairs itself easily
The only human tissue that can be transplanted without fear of rejection
Cornea
(Vascular Layer)
Lines most of the internal surface of the sclera
Blood-rich nutritive tunic
Pigment prevents light from scattering;
contains melanocytes
Choroid Layer
smooth muscle; consists of ciliary processes and ciliary muscle
Ciliary processes: protrusions or folds on the internal surface of the ciliary body; contains blood capillaries that secrete aqueous humor (fills the cavity of the anterior segment of eyeball)
Ciliary body
pigmented layer that gives eye color; regulates the amount of light entering the eyeball through the pupil (round opening in the iris)
Iris
Contains receptor cells (photoreceptors):
Rods and Cones
Retina
—-: most are found towards the edges of the retina
Allows dim light vision and peripheral vision
Perception is all in gray tones
——: allow for detailed color vision
Densest in the center of the retina
Rods: most are found towards the edges of the retina
Allows dim light vision and peripheral vision
Perception is all in gray tones
Cones: allow for detailed color vision
Densest in the center of the retina
——: area of the retina with only cones; area of highest visual acuity
——: no photoreceptors, also known as the blind spot
——: exact center of the posterior portion of the retina
Fovea centralis: area of the retina with only cones; area of highest visual acuity
Optic disc: no photoreceptors, also known as the blind spot
Macula lutea: exact center of the posterior portion of the retina
Biconvex crystal-like structure
Held in place by a suspensory ligament attached to the ciliary body
They help focus images on the retina to facilitate clear vision
Lens
Internal muscles are controlled by the autonomic nervous system
Eye Reflexes
——reflex: bright light causes pupils to constrict through action of radial, circular, and ciliary muscles
——-pupillary reflex: viewing close objects causes accommodation
Photopupillary reflex: bright light causes pupils to constrict through action of radial, circular, and ciliary muscles
Accommodation pupillary reflex: viewing close objects causes accommodation
——reflex: bright light causes pupils to constrict through action of radial, circular, and ciliary muscles
——-pupillary reflex: viewing close objects causes accommodation
Photopupillary reflex: bright light causes pupils to constrict through action of radial, circular, and ciliary muscles
Accommodation pupillary reflex: viewing close objects causes accommodation
—– inhibited rod function that hinders the ability to
see at night
—–genetic condition that results in the inability to see certain colors; due to lack of one type of cone (partial color blindness)
Night blindness
inhibited rod function that hinders the ability to
see at night
Color blindness
genetic condition that results in the inability to see certain colors; due to lack of one type of cone (partial color blindness)
—- can cause blindness due to increasing pressure within the eye
—–loss of the same side of the visual field of both eyes resulting from damage to the visual cortex on one side only
Glaucoma
can cause blindness due to increasing pressure within the eye
Hemianopia
loss of the same side of the visual field of both eyes resulting from damage to the visual cortex on one side only
T or F
Houses two senses:
Hearing
Equilibrium
True
collects sound waves and channels them inward
External ear
conveys sound vibrations to the oval window
middle Ear
houses the receptors for hearing and equillibrium
Inner ear
What part of the ear is Pinna (auricle): and External auditory canal (or meatus): located?
External
—–: flap of elastic cartilage shaped like the flared end of a trumpet
—: Narrow chamber in the temporal bone
Line with skin
Ceruminous glands are present
Ends at the tympanic membrane (eardrum)
Pinna (auricle): flap of elastic cartilage shaped like the flared end of a trumpet
External auditory canal (or meatus):
Narrow chamber in the temporal bone
Line with skin
Ceruminous glands are present
Ends at the tympanic membrane (eardrum)
The bones of the tympanic cavity are responsible for producing vibrations that came from the soundwaves; the bones transfer the sound to the inner ear; three bones span the cavity:
Ossicles:
- Malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
(Bony Labyrinth)
Includes sense organs for hearing and balance
Filled with perilymph (fluid)
A maze of bony chambers within the temporal bone:
Cochlea (hearing)
Vestibule
Semicircular canals
Inner Ear
Located within the cochlea
Receptors = hair cells on the basilar membrane
Gel-like tectorial membrane is capable of bending hair cells
Cochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobe
Organ of Corti
Physiology of Hearing
The auricle directs sound waves into the external auditory canal.
Sound waves striking the eardrum cause it to vibrate.
The central area of the eardrum connects to the malleus, which also starts to vibrate. The vibration is transmitted from the malleus to the incus and then to the stapes.
As the stapes move back and forth, it pushes the oval window in and out.
The movement of the oval window sets up fluid pressure waves of the cochlea.
The fluid pressure waves are transmitted from the scala vestibuli to the scala tympani and eventually to the membrane covering the round window.
As the pressure waves deform the walls, this creates pressure waves inside the cochlear duct.
The pressure waves bend the hairs of the spiral organ and stimulate the vestibulocochlear (VII) nerve.
T or F
Taste and smell are most acute at birth and decrease in sensitivity after age 40 as the number of olfactory and gustatory receptors decreases
True
Age-related ear problems: (2 items)
EXPLAIN
Presbycusis: type of sensorineural deafness that may result from otosclerosis
Otosclerosis: ear ossicles fuse
T or F
The newborn infant can’t hear sounds, but initial responses are reflexive
By the toddler stage, the child is listening critically and beginning to imitate sounds as language development begins
False
The newborn infant can hear sounds, but initial responses are reflexive
By the toddler stage, the child is listening critically and beginning to imitate sounds as language development begins
“old vision” results from decreasing lens elasticity that accompanies aging
Presbyopia
—– “crossed eyes”; results from unequal pulls by the external eye muscles in babies
——: conjunctivitis resulting from gonorrhea in the mother; baby’s eyelids are swollen, and pus is produced
Strabismus: “crossed eyes”; results from unequal pulls by the external eye muscles in babies
Ophthalmia neonatorum: conjunctivitis resulting from gonorrhea in the mother; baby’s eyelids are swollen, and pus is produced
T or F
Special sense organs are formed early in childhood development
Maternal infections during the first 5 or 6 weeks of motherhood may cause visual abnormalities as well as sensorineural deafness in the developing child
FALSE
Special sense organs are formed early in embryonic development
Maternal infections during the first 5 or 6 weeks of pregnancy may cause visual abnormalities as well as sensorineural deafness in the developing child
T or F
Congenital ear problems usually result from missing pinna and closed or missing external acoustic meatuses
Vision requires the most learning
The infant has poor visual acuity (is farsighted) and lacks color vision and depth perception at birth
The eye continues to grow and mature until age 8 or 9
Ture
Anatomy of the maculae:
Hair cells are embedded in the otolithic membrane
Otoliths (tiny stones) float in a gel around the hair cells
Movements cause otoliths to bend the hair cells
Maculae
receptors in the vestibule
Reports on the position of the head
Sends information via the vestibular nerve
eceptors in the semicircular canals
Crista ampullaris
T or F
The mouth contains 10-100 million receptors for the sense of smell
The optical epithelium occupies the upper portion of the nasal cavity and consists of 3 types of cells
The nose contains 10-100 million receptors for the sense of smell
The olfactory epithelium occupies the upper portion of the nasal cavity and consists of 3 types of cells
T or F
The mouth contains 10-100 million receptors for the sense of smell
The optical epithelium occupies the upper portion of the nasal cavity and consists of 3 types of cells
The nose contains 10-100 million receptors for the sense of smell
The olfactory epithelium occupies the upper portion of the nasal cavity and consists of 3 types of cells
Olfactory Pathway
On each side of the nose, about 40 bundles of the slender, unmyelinated axons of olfactory receptor cells extend through about 20 holes in the cribriform plate of the ethmoid bone.
Axons of olfactory receptors form the olfactory (I) nerves, which convey nerve impulses to the olfactory bulbs.
From there, impulses conduct via the olfactory tract to the limbic system, hypothalamus, and cerebral cortex (temporal lobe).
Taste has types of receptors:
EXPLAIN
Sweet: presence of aminoacids or saccharides
Sour: presence of hydrogen ions or acids
Bitter: presence of alkaloids
Salty: presence of metal ions
Umami: presence of glutamate or MSG
—- buds house the receptor organs
Location of —- buds are mostly on the tongue
The tongue is covered with projections called papillae
Taste buds house the receptor organs
Location of taste buds are mostly on the tongue
The tongue is covered with projections called papillae
—- buds house the receptor organs
Location of —- buds are mostly on the tongue
The tongue is covered with projections called papillae
Taste buds house the receptor organs
Location of taste buds are mostly on the tongue
The tongue is covered with projections called papillae
—-papillae: sharp with no taste buds
—-papillae: rounded with taste buds
—–papillae: large papillae with taste buds
Filiform papillae: sharp with no taste buds
Fungiform papillae: rounded with taste buds
Circumvallate papillae: large papillae with taste buds
Impulses are carried to the gustatory complex by several cranial nerves because taste buds are found in different areas
CN VII, facial nerve
CN IX, glossopharyngeal nerve
CN X, vagus nerve
Gustatory Pathway
3 cranial nerves innervate the taste buds: facial (VII), glossopharyngeal (IX), and vagus (X)
Impulses for taste conduct to the medulla oblongata, limbic system, hypothalamus, thalamus, and the primary gustatory area in the parietal lobe of the cerebral cortex
Gustatory Pathway
3 cranial nerves innervate the taste buds: facial (VII), glossopharyngeal (IX), and vagus (X)
Impulses for taste conduct to the medulla oblongata, limbic system, hypothalamus, thalamus, and the primary gustatory area in the parietal lobe of the cerebral cortex
